An advanced, nondestructive via in-hole characterization method is described in this article. Via profiling can be very beneficial as technology node shrinks with more back end of the line processing schemes. This method of real time, nondestructive 3D via imaging was used to characterize via bottom anti-reflection coating fill process for dual-damascene formation used extensively in Cu metallization. The results showed that atomic force microscopy (AFM) can profile deep vias with very good accuracy and can help in real-time process loop feedback. The AFM measurements reported in this article have been done using Veeco's metrology AFM SXM-320. This tool provides a patented ''deep trench'' mode of operation. The mode is specifically designed to use tips with very high aspect ratios. It is shown that AFM can measure via profiles, depth, sidewall roughness and critical dimensions.